The nuclear matrix (NM) proteins, a complex nonhistone protein fraction comprising less than 0.4% of the total cellular proteins, are isolated using a recently devised procedure. When the composition of this fraction is examined in a number of diverse cell lines, the cell type specific (CTS) nuclear matrix proteins are conserved in cell lines with a common tissue of origin. Tumor specific nuclear matrix proteins appear in highly malignant cell lines. The expression of tumor specific proteins may correspond to the malignant grade of the tumor from which the cell line was derived. The NM proteins from a number of cell types will be identified by molecular weight and isoelectric point. This database will be used to analyze the complex patterns of biopsy samples. Monoclonal antibodies will be generated using purified, CTS and tumor specific proteins as antigens. These monoclonal probes will be used to screen NM preparations from a number of cell lines and biopsy specimens. The composition of the NM fraction in normal human breast, colon and cervical biopsy specimens will be examined. Biopsy samples will be grown on collagen gels in vitro, labeled with 35S methionine and the entire biopsy will be fractionated. The proteins of the (NM) closely reflect the differentiated and malignant state of an individual cell type. The present proposal suggest a series of experimental analyses to determine if the cell culture observations extend to human tissue The experiments using normal and malignant biopsies will determine whether the specific NM proteins might also provide reliable diagnostic markers for breast, colonic and ovarian cancers. The CTS and tumor specific NM proteins will ultimately be analyzed for their DNA binding properties and their association with specific chromosomal domains.